For example, in a multistage forging press machine in which a plurality of forging portions provided with dies and punches are provided in parallel in a horizontal direction, a fixed mold provided with the dies is fixedly attached to a frame side, and a movable mold provided with the punches is fixedly attached to a ram side.
Those molds are replaced suitably to produce a product having a different shape. The molds may be heavy goods as heavy as several tons in some cases. Work of replacing the molds is not easy. It has been therefore desired to improve workability in the work.
In a typical multistage forging press machine, the top of a frame is open. Therefore, a crane or a dedicated mold hanging device is used for the work of mold replacement through the open space.
However, when a crane is used for replacing a mold, the work time becomes long. Thus, the operating rate of equipment deteriorates to impair productivity.
On the other hand, when a dedicated mold hanging device is installed for replacing a mold, the structure of the mold hanging device is always placed on/above the press machine. During maintenance work of the machine, there arises a problem that workability deteriorates due to interference with the structure of the mold hanging device, or the like.
The following Patent Document 1 discloses an invention about a “mold replacement apparatus”. In the mold replacement apparatus, a plurality of conveyance rollers are disposed in a horizontal direction on a mold mounting surface to which a mold is fixedly attached. In order to replace the mold, the mold is moved in the horizontal direction by use of the conveyance rollers so that the mold can be carried out or in.
The following Patent Document 2 discloses an invention about a “multistage horizontal forging apparatus”. In the multistage horizontal forging apparatus, a movable mold and a fixed mold are attached to a ram and a frame respectively, through split blocks. In addition, rail grooves extending horizontally are provided in the split blocks respectively so that the movable mold and the fixed mold can be extracted horizontally together with the split blocks by guidance of the rail grooves in order to replace the molds.
According to Patent Document 1 and Patent Document 2, a mold is extracted horizontally by use of the conveyance rollers or the like in order to replace the mold. Thus, it is not necessary to replace the mold using a crane or the like as in the background art, but it is possible to replace the mold comparatively easily.
However, an engagement part for positioning or the like is generally located between a mold and a mold mounting surface to which the mold is fixed. Therefore, in order to carry out and horizontally move the mold toward the outside of the apparatus as in those Patent Documents, not only it is necessary to cancel a fixing force with which the mold is fixed to the mold mounting surface, but it is also necessary to separate the heavy mold from the mold mounting surface until the engagement between the mold and the mold mounting surface is completely cancelled.
According to Patent Documents 1 and 2, a conveyance unit such as the conveyance rollers for horizontally carrying out and move the mold is simply added and fixed. In those Patent Documents, there is no suggestion about any specific configuration for performing a series of operations, that is, cancelling the fixing force and then separating the mold from the mold mounting surface so that the mold can be carried out and moved.
Patent Document 1: JP-A-10-44157
Patent Document 2: JP-A-2011-212733